Bent ply-wood and method of bending same



0.1H. BASQUIN. BENT FLY WOOD-AND METHOD 0F BENDINGSAIVIE. APPLICATION FILED NOV. I4, 1919.

Patented July 13, 192,0.4

2. SHEETS-SHEET i.

i inlener.

(UNITED STATES PATENT oFFlcn.

DLIN- E.- IBASQ'UIN, EVANSTON, ILLINOIS, .ASSIGNOR TO HASKELITE-MANUFAO- i TUBING CORPORATION, A CORPORATION OF NEW YORK..

BENTPIY-WOO'D AND METHOD OF BENDINGj-SAME.

Specication of Letters Patent.

Application led November 14.-, 1919. Serial No. 337,9G.

Be it known'that I, OLIN H. BAsQmma citizenof the United States, residing at Evanston, county of Cook, State of Illinois, have invented a certain new and useful proveme'nt in Bent Ply-Woodand Methods of Bending Same, and declare the following to be'a full, clear, and exact vdescription of the same,'such aswill enable others skilled in the art to which it pertains to make and use the same, reference being hadto the accompanying drawings, which forma part of this specification.

In making a sharp bend in three-ply wood veneer in which the grain of one ply is transverse to another, .there is danger. of either splitting the' wood on the tension side or causing it to buckle on the compression side. rlhe object'of the present invention is to produce`. a multiple ply structure having therein a sharp bend, thejstructure being. so

arranged. that when it is bent from a Hat state thediiilculties heretofore pointed out will be avoided. Viewed in anotherof its aspects my invention may be said to have for its obj ect a simlse ple and novel method of forming a sharp bend in a multiple ply sheet of wood.

lt is well known that wood cannot be stretched materially in any direction. lt is also well known that wood 'cannot readily be compressed except transversely to the grain. lf it be attempted to make a sharp bend in say a three-ply sheet in which the grain in the inner layer is at right angles to the grain yin the outer layers it-must follow that there is either on the `tension or the compression-.side of the sheet a material which is not adapted to withstand the stresses coming upon it and consequently, there is` apt to be either a buckling on the compression sidel or a splitting of the material on the tension lin accordance with my invention I reduce the number of layers of wood in the zone where the bend is to occur so'that the tension stresses are parallel with the grain in the outer layerand the compression stresses are transverse to the grain of the layer on the inner side of the bend. The ultimate extent ofthe reduction is of course to two layers; but if there are more than three layers in a Y sheet it will suffice if one or more layers are cut away so aste permit the compresslon stresses in the bending process to be .across v'claims; but, fora full understanding of my 1nvent1on and of its objects and advantages,

reference may be had to the following detailed description taken in connectionwith the accompanying drawings, wherein:

Figure 1 is an edge view of a three-ply sheet ready to be bent; Y Fig. 2 is a view similar to Fig. l, showing the sheet after it hasbeenbent to form a right-angled corner; i

Fig. 3 is a perspective view. of the bent sheet;

Fig. 4, Fig. 5 and Fig. 6 are views similar to Fig. l showing fragments of several modivbending zones or ed forms of reduced panels; Fig. v7v is an edge view of a series of dat sheets arranged in a stack preparatory to being steamed to place them in condition for bending; and

` Fig. 8 is a section of a fragment of the Fig. 7, together with the steam-supplying means. l

Referring to Figs. l, 2 and 3 of the Y ings, 1, 2 and 8 represent the plies of a threeply sheet of wood. The grain in the inner ply or layer, 2, is arranged at right angles to the grain in the two'outer plies or layers. Assuming thatthe sheet is to be bent sharply along a line parallel with the grain inthe inner layer, that outer layer which' it is -intended shall lie on the inner side of the angle is cutaway so as to leave a panel, d, of con- 'sey draw- Y roo condition illustrated in Fig. 2, the material of the panel, d', is compressed so as to pelmit the outer layer, thatis the layer l, to

adjust itself substanti lly the same man-V iio method of steaming sheets to be bent in the.

manner heretofore explained. Thu'sin Fig.

7 there are shown four sheets, 5, 6, 7 and 8,

having bending panels, 90 and 10, similarly disposed. Ona suitable flat supporting surface, 11, isplaced a heavy plate, 12,.having channels, 13 and 14, spaced apart a distance corresponding to the spacing between the panels 9 and 10. The sheet 5 is laid upon the member 12 with its panels, 9 andlO,

registering with the channels" 13 and 14. A.

plate, 15, similar to the plate 12, is then laid upon the sheet'; the sheet,` 6, being laid fupon the plate 15 andthe stack 'being completed by alternating channeled plateswith sheets to be treated. vA vertical troughshaped manifold, 16, v extends over one end of -each vertical series of channels, A'13 and vlet; and, when steam is admitted to the manifolds through pipes, 17, it is distributed through the several channels and acts on the.

ply-wood to soften it and place it in a condition for bending.

Instead of completely cutting away the layer 3, slitsor saw-cuts, 20, 'may be cut at properly directed to take the compression,

intervalsin this layer in the direction of the length ofthe bending anel. or zone as illustrated in Fig. 4. p

Furthermore, if vthere are more than three layers as, for example, five layers as illustrated at 21, .22, 23, 24 and 25 in Fig. 5, wherein the second layer, 24, from the inner side of the bent structure has the .grain only the inner layer, 25, need lbe cut away to form a bending zone or panehlif, because.

the layers 22 and 23 lying between the layers 21 and 25 will be supported by these latter layers'. In the case of a thick sheet illustrated as a whole at'26 in Fig. 6, that is aA sheet containing a comparatively large number of-lalyers, it may be advisable to cut away material Afrom approximately half of the layers in the region of the bending zone 'or panel, 27.

Whlle I have illustrated ande-described with. particularity only a single .preferred form of my invention, I do not desire to be limited. to the exact `structural details thus i cat1on.

ilustrat'ed and described; but vintend 'to cover all forms and arrangements which come within the terms employed inthe definitions of my invention constituting the ap.- pended claims. 1 g p I claim: .l Y V1. A. sharply-bent sheet of plywood of more than two plies having the number o f plies inthe zone in which the bend occursreduced to vtwothe inner of which. has its grain extending lengthwise of the angle or corner andthe outer of which has its grain extending transversely. 2. The method of forming sharply-bent 75. sheets of plywood having more'than two plies which consists in reducing the number of plies in each sheet in the bending zone to two -havin the grain transverse to .eachgother, placing the sheets in a stacl made up 8 of sheets alternating with spacing plates providedv with lchannels registering with the :reduced portions' of the sheet, introducing .steam into the channels, and then. bending the sheets in a directionto bring thecompression stresses transverse Vto the grain of that ply in the reduced zone .which lies on the. inner side of the'angle in the completed structure.

e. The methodf forming@ sharply-bent 9o sheet of plywood containing morethan two plies, which consists in reducmg the num-I ber of plies in the zone in whichthe bending l is to occur to two having the grainltransverse to each other, subjectmg saldzon of the sheet to heat and moisture to render it pliable, and then bending the sheet in a direction to bring .the compression stresses transverse to that ply in the reduced z one which is to lie on the inner side ofthe fangle in the completed structure.

.4. A sharply bent sheet of ply-wood'having `a layer on the'outer side of the bend 1n which thegrain extends in the direction of the tension stresses and having ma'terlal 105 removed from one or more layers on the inner sideof the bend soas to expose a layer inwhich the grain extends lengthwise of` the angle or. corner, that is transverse tothe compression stresses.

5. Thev method of forminga sharply bent sheet of ply-wood which oonslsts in reducing the number of layers in the sheet in thejzone in which the bending is to occur so as .t0

have an outer layer in which the grain runs in the direction of thetension 'stresses when 'the sheet is bent and an exposed inner layer in Vsaid zone in which the grain extends transverse to the compression stresses produced by the bending' operation, sub]ect in'g said 120 zone of the sheet to heat and morstureto render it pliable, and then bending the sheet.' V In testimony whereof, I slgntlnsV speci- 

